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Mittwoch, 23. April 2014

What Apple Missed to Fix in iOS 7.1.1

A few weeks ago, I noticed that email attachments within the iOS 7 MobileMail.app are not protected by Apple's data protection mechanisms. Clearly, this is contrary to Apple's claims that data protection "provides an additional layer of protection for (..) email messages attachments".

I verified this issue by restoring an iPhone 4 (GSM) device to the most recent iOS versions (7.1 and 7.1.1) and setting up an IMAP email account1, which provided me with some test emails and attachments. Afterwards, I shut down the device and accessed the file system using well-known techniques (DFU mode, custom ramdisk, SSH over usbmux). Finally, I mounted the iOS data partition and navigated to the actual email folder. Within this folder, I found all attachments accessible without any encryption/restriction:

To verify that data protection was actually enabled, I also tried to access the Protected Index file (email message database). As expected, access to that file was not permitted.

# xxd Protected\ Index
xxd: Protected Index: Operation not permitted

Note: I was also able to reproduce this issue on an iPhone 5s and an iPad 2 running iOS 7.0.4.

I reported these findings to Apple. They responded that they were aware of this issue, but did not state any date when a fix is to be expected. Considering the long time iOS 7 is available by now and the sensitivity of email attachments many enterprises share on their devices (fundamentally relying on data protection), I expected a near-term patch. Unfortunately, even today's iOS 7.1.1 did not remedy the issue, leaving users at risk of data theft. As a workaround, concerned users may disable mail synchronization (at least on devices where the bootrom is exploitable).

1 It turned out that POP or ActiveSync email accounts behave the same way.

Hello Mr. Seitzer,as the author, Andreas Kurtz, has written in Note1 in hier post, this also affects ActiveSync Accounts. According to [1], in my opinion, the shown security issue affects Exchange accounts in the same way it affects Pop/Imap acounts.Regards,Simon Streicher

Hi Andreas,Thanks for this insight. Once again I wish Apple would be a bit more open in it's communication about such issues.Although I guess it is quite clear, that this issue is not fixed by the hardware update in later devices alone, since you have tested it with iOS 7.0.4: Does this also affect devices such as iPhone 5s with iOS 7.1.1.?Regards,Erik